Creating special device names

You can also use symbolic prefixes to create special device
names. For example, if your modem was on
/dev/ser1, you could create a symbolic prefix
of /dev/modem as follows:

ln -Ps /dev/ser1 /dev/modem

Any request to open /dev/modem will be
replaced with /dev/ser1. This mapping would
allow the modem to be changed to a different serial port
simply by changing the symbolic prefix and without affecting
any applications.